Vehicle interior article of skin-integrated laminate, method for manufacturing non-foaming polyurethane resin and method for manufacturing skin-integrated laminate using the same

ABSTRACT

The present invention is directed to skin-integrated laminates and their use as vehicle interior articles, in which the laminates feel comfortable to the touch and have a high quality of external appearances. The invention also relates to a method for manufacturing these non-foaming polyurethane resins for use as design skins in vehicle interior articles and to a method for manufacturing a skin-integrated laminate from these non-foaming polyurethane resins, with both methods having increased productivity and lower cost, and without any adverse influence on the work environment. The non-foaming polyurethane resin forms a design skin surface by a reaction injection molding process, in which (I) a polyol mixture of (1) a polyol, (2) a chain extender which is 1-methyl-3,5-diethyl-2,4-diaminobenzene and/or 1-methyl-3,5-diethyl-2,6-diaminobenzene, (3) a catalyst, and (4) optionally, an auxiliary agent, and (II) a polyisocyanate compound, are reacted. The surface hardness of the non-foaming polyurethane resin, as measured by an Asker A hardness meter, is from 30 to 70.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/408,197, which was filed on Apr. 20, 2006 (now U.S. Pat. No.7,572,404), which claims the right of priority under 35 U.S.C.§119(a)-(d) of Japanese Patent Application No. 2005-132466, which wasfiled on Apr. 28, 2004.

The present invention relates to a method for manufacturing anon-foaming polyurethane resin which is suitable as the skin for thedesign faces of vehicle interior articles including articles such asinstrument panels and door trims, and to a method for manufacturing askin-integrated laminate from these non-foaming polyurethane resins.

BACKGROUND OF THE INVENTION

Many kinds of materials manufactured by various molding processes havebeen used as skins for vehicle interior articles. For example,previously used materials include articles manufactured byvacuum-molding vinyl chlorides (PVC), articles manufactured byvacuum-molding or powder-molding thermoplastic olefins (TPO), articlesmanufactured by slush-molding thermoplastic polyurethanes (TPU), andarticles manufactured by spraying or reaction injection molding (RIM)polyurethane raw materials (i.e., polyurethane liquid mixtures obtainedby impinging and mixing two liquids, i.e. a liquid polyol and a liquidisocyanate, under a high pressure). In general, polyurethane rawmaterials are subjected to reaction injection molding to provide moldedarticles.

The molded articles of these materials have some defects, however. Forexample, PVC molded articles are undesirable since they release dioxinand chlorinated by-products while decomposing, thus polluting theenvironment. In addition, these materials are also hard to scrap orrecycle.

TPO molded articles prepared by vacuum molding are undesirable as theyfeel hard and uncomfortable to touch. Molded articles prepared by powdermolding are poor in production efficiency, as are the PVC moldedarticles, and thus these are inferior in cost-effectiveness since themolding processes require a relatively long time and consume a lot ofenergy.

TPU molded articles by slush molding are improved in terms of their feeland touch, but they are also poor in production efficiency andcost-effectiveness. The slush mold process also requires a relativelylong time and a lot of energy.

Polyurethane molded articles which are manufactured by sprayingpolyurethane raw materials are an improvement over the conventional TPUmolded articles produced by slush molding, because of the highproductivity thereof. Since these polyurethane molded articles aregenerally manufactured from highly reactive raw materials, highproductivity can be expected. Over-spray of the raw materials results infumes and vapors which pose various industrial hygiene concerns. This isunavoidable, however, due to the process of spraying the raw materials.Consequently, the removal of the over-sprayed raw materials around themolds, which requires a considerable amount of time, is indispensable.As a result, the productivity is lowered due to the time spent for theremoval of these over-sprayed raw materials. In addition, the quantitiesof raw materials which are used in the spraying process are increasedbecause of the unavoidable over-spray of the raw materials. This alsoleads to an undesirable higher cost, as well as to pollution in the workenvironment.

The spraying process also has disadvantages in that the polyurethane rawmaterials which are sprayed are subject to the influences of atmospherictemperatures and humidity, and tend to absorb the water content from theair, or the air itself will form bubbles in the resultant articles. As aresult of these influences, the raw materials tend to foam. In anothersituation, when molding a large vehicle interior article, it isnecessary to spray the polyurethane raw material into the mold manytimes, which results in the layers of the polyurethane materials tendingto have variable densities and hardness at the interfaces between eachof the layers formed before and after the spraying of the polyurethaneraw material. Thus, the surface of the resultant article feelsinharmonious in touch. For these reasons, the resultant skin is variedin density, thickness, hardness and feeling.

A molded article obtained by the reaction injection molding (RIM) ofpolyurethane raw materials can have a highly designable appearance,because the unevenness of a surface can be precisely reproduced. Inaddition, the volume of the raw material in the mold is constant, sothat the resultant article is stabilized in density, thickness andhardness. For these advantages, this method has been employed in a widerange of fields. In general, the thickness of a skin for use as thedesign surface of a vehicle interior article ranges from about 0.5 toabout 3.0 mm, which is thinner than ordinary molded articles produced bya RIM process. Therefore, the raw material has higher flow resistance.In consideration of ensuring the filling of the raw material completelyto the tip ends of the article, it is indispensable to lower thereactivity of the raw material. For this reason, the cure time (i.e. thetime from the injection of the polyurethane raw material into the moldto the start of opening the mold) becomes longer, and results in poorproductivity.

Skin-integrated vehicle interior articles such as instrument panelswhose skins are used as design surfaces and door trims, and inparticular, vehicle instrument panels, must not only have physicalproperties such as UV stability, wear resistance, expandability for airbag and durability, but also demand a high quality of externalappearances and comfortable feeling (i.e. comfortable to the touch).Under these circumstances, it is desired to find a method formanufacturing an integrally molded laminate which comprises a skin as adesign surface, a core material supporting the skin, and optionally, asemi-rigid polyurethane foam for reducing the impact between the skinand the core material, in which the method is characterized by a shortercycle time and the yield is improved, giving higher productivity and atlower production cost.

Materials which feel comfortable in terms of touch and which can bemanufactured in high productivity and at lower production cost have beendemanded as skins for the interior articles of vehicles, in particular,automobiles. Previously, there have been several proposals known forthese materials and their processes of manufacturing them.

The reference JP-A-52-142797 discloses a method for manufacturing apolyurethane elastic molded article which comprises using a specifiedpolyol and a specified aromatic diamine. In this reference, a method ofmolding a polyurethane elastomer in a shorter time is described whichrequires a specified polyol and a specified aromatic diamine. Accordingto this publication, the molded articles are relatively large exteriorparts, with weights of 3 to 10 kg or more, such as bumpers for vehicles,etc. In the Examples of this publication, articles with a thickness of 4mm, having a Shore A hardness of as relatively high as 84 or more, areproduced. By comparison, the skins in accordance with the presentinvention for use as the design surfaces of vehicle interior articlesare not of this type.

JP-A-53-86763 discloses a method for forming a foam layer in tightcontact with a skin. This method comprises the steps of forming a skinby the reaction injection molding of a polyurethane raw material in thecavity of a mold; allowing the skin to remain in the mold and removingthe first core part; placing a second core part which is capable ofshaping a cavity equivalent to the thickness of a foam layer, instead ofthe first core part; and injecting a foaming material into the cavity,thereby forming the foam layer in tight contact with the skin. Thisreference proposes a method of molding an interior article integral witha skin. However, this publication only describes that the material forthe skin is of the urethane type, and does not disclose any detailsabout the composition of a urethane material suitable for this method,the density of urethane and/or the surface hardness of the skin.

The reference JP-A-2003-19056 discloses a seat cushion using a seamlessskin material and a method for manufacturing the same. This publicationproposes a seat cushion comprising a foam article having practically thesame contour as that of the seat cushion, and a seamless skin materialadhered and integrated into the surface and side faces of the foamarticle. However, this reference also only describes that the materialfor the skin is of the urethane type, and does not describe or discloseany details about the composition of a urethane material suitable forthis method, the density of urethane and/or the surface hardness of theskin material.

-   -   Patent Literature 1: JP-A-52-142797    -   Patent Literature 2: JP-A-53-86763    -   Patent Literature 3: JP-A-2003-19056

At this time, there is no satisfactory skin which feels comfortable intouch, and has a high quality of outer appearance for application as askin for a vehicle interior article, and which can be manufactured inhigh productivity and at lower cost without having any adverse influenceon the work environment and/or nature. Also, there is no satisfactorymethod currently available for manufacturing a skin-integrated laminatecomprising such a skin.

SUMMARY OF THE INVENTION

The objects of the present invention are to provide skin-integratedlaminates which are suitable for use as vehicle interior articles, whichfeel comfortable to touch and have a high quality of externalappearances, which can be manufactured at higher productivity rates andat lower cost, without having any adverse influence on the workenvironment and nature. Another object is to provide a method formanufacturing a non-foaming polyurethane resin which is suitable for useas the skin of a vehicle interior article, and to provide a method formanufacturing a skin-integrated laminate from the non-foamingpolyurethane resin.

A result of various efforts to solve the above problems has resulted inthe discovery of a method, as described below, for manufacturing anon-foaming polyurethane resin which is suitable for use in skins forvehicle interior articles, and a method for manufacturing askin-integrated laminate comprising the non-foaming polyurethane resin.

The present invention is directed to a vehicle interior article which isa skin-integrated laminate comprising a core material and a skin of anon-foaming polyurethane resin, which serves as a design face. In thisvehicle interior article, this skin of non-foaming polyurethane resin isobtained by a reaction injection molding process, in which thenon-foaming polyurethane resin comprises a polyol mixture (I) and apolyisocyanate compound (II).

Suitable polyol mixtures (I) comprise:

-   (1) a polyol,-   (2) a chain extender which comprises    1-methyl-3,5-diethyl-2,4-diaminobenzene,    1-methyl-3,5-diethyl-2,6-diaminobenzene and mixtures thereof, with    the chain extender being present in an amount of 2.0 to 7.0 parts by    weight, based on 100 parts by weight of (1) the polyol mixture,-   (3) at least one catalyst, and-   (4) optionally, one or more auxiliary agents.

The non-foaming polyurethane resin produced herein has a surfacehardness of 30 to 70, as measured with an Asker A hardness meter.

The present invention also provides a vehicle interior article whichcomprises the above skin-integrated laminate having a semi-rigidpolyurethane foam between the core material and the skin, as the designface, formed of the non-foaming polyurethane resin as described above.

Further, the present invention provides a method for manufacturing anon-foaming polyurethane resin for use in vehicle interior articleswhich comprises reaction injection molding of (I) a polyol mixturecomprising (1) a polyol, (2) a chain extender, (3) at least one acatalyst, and, (4) optionally, one or more auxiliary agents, and (I) apolyisocyanate compound (1). In this process, the chain extender (2)comprises 1-methyl-3,5-diethyl-2,4-diaminobenzene,1-methyl-3,5-diethyl-2,6-diaminobenzene, or mixtures thereof, and ispresent in an amount of 2.0 to 7.0 parts by weight, based on 100 partsby weight of the poly mixture. The non-foaming polyurethane resin formsin a cure time of 30 to 100 seconds so that the thickness of theresultant layer can be 0.5 to 3.0 mm, with the condition that the geltime of a reaction mixture of (I) the polyol mixture and (II) thepolyisocyanate compound is 5.0 to 15.0 seconds. In addition, theresultant non-foaming polyurethane resin has a surface hardness of 30 to70, as measured with an Asker A hardness meter.

Furthermore, the present invention provides a method for manufacturing askin-integrated laminate which comprises a skin of the non-foamingpolyurethane resin and a core material. This method comprising the stepsof:

-   (1) installing the core material to a core part of a mold,-   (2) applying a mold release agent on the surface of a cavity part of    the mold,-   (3) optionally, forming or applying a coating film by coating the    surface of the cavity part of the mold,-   (4) closing the core part and the cavity part of the mold,-   (5) reaction injection molding a liquid mixture of (I) the polyol    mixture and (II) the polyisocyanate compound, and-   (6) removing an integrally molded article.

The present invention also provides a method for manufacturing askin-integrated laminate which comprises a skin of the non-foamingpolyurethane resin, a semi-rigid foam and a core material. This methodcomprises the steps of

-   (1) applying a mold release agent on the surfaces of a core part and    a cavity part of a mold for forming a skin surface which is suitable    for use as a design face,-   (2) optionally, forming or applying a coating film on the surface of    the cavity part by a coating process,-   (3) closing the core part and the cavity part of the mold,-   (4) reaction injection molding of a liquid mixture of (I) the polyol    mixture and (II) the polyisocyanate compound,-   (5) removing a molded article of the non-foaming polyurethane resin    which is suitable as the skin for the design face,-   (6) setting the molded article of the non-foaming polyurethane resin    obtained from step (5), in the cavity part of a mold for shaping a    foam,-   (7) installing the core material to the core part of the above    foam-shaping mold,-   (8) injecting or pouring a semi-rigid polyurethane foam onto the    molded article of the non-foaming polyurethane resin which was set    in the cavity portion of the above foam-shaping mold employed in the    step (6), with the mold being either opened or closed, and-   (9) removing the molded article integrated with the skin.

DETAILED DESCRIPTION OF THE INVENTION

A skin-integrated molded article which feels soft and comfortable intouch, and has a high quality of external appearance, and which issuitable to be used as a skin for a design face of an interior articleof a vehicle such as, for example, an automobile can be manufacturedwith higher productivity and at lower cost, without having any adverseinfluence on the work environment and nature. In accordance with thepresent invention, a laminate comprising a skin and a core material, ora laminate comprising a skin, a semi-rigid urethane foam and a corematerial, either of which has excellent properties, can be manufactured.

Examples of suitable polyether polyols to be used as (1) the polyolcomponent of (I) the polyol mixture in the present invention includeadduct compounds obtained by the addition of alkylene oxides, such asethylene oxide and propylene oxide, to hydroxyl group-containingcompounds, such as propylene glycol, diethylene glycol, glycerin,trimethylolpropane and pentaerythritol, and/or amino group- or hydroxylgroup-containing compounds such as monoethanolamine, diethanolamine andtriethanolamine, and/or amino group-containing compounds such asethylenediamine and diaminotoluene.

Preferably, the polyether polyol suitable for use as (1) the polyolcomponent herein has an average functionality of about 2.0 to about 3.0,a hydroxyl value of about 16.8 to about 56 mg KOH/g, and an endoxyethylene unit content of about 10% to 25% by weight. More preferably,the polyether polyol has an average functionality of about 2.0 to about2.5, a hydroxyl value of about 28 to about 50 mg KOH/g, and an endoxyethylene unit content of about 15% to about 20% by weight.Preferably, the polyether polyol has a molecular weight of about 2,000(when having an average functionality of about 2.0 and a hydroxyl valueof about 56 mg KOH/g) to about 10,000 (when having an averagefunctionality of about 3.0/a hydroxyl value of about 16.8 mg KOH/g).When the average functionality of the polyether polyol is in the rangeof about 2.0 to about 3.0, the curing time becomes suitably longer, andthe elongation of the resultant molded article becomes higher. When thehydroxyl value of the polyether polyol is in the range of about 16.8 toabout 56 mg KOH/g, the flowability of the liquid mixture comprisingcomponents (I) and (II) (which refers to the liquid mixture of (I) thepolyol mixture, and (II) the polyisocyanate compound in the presentinvention) becomes higher, so that the mixture liquid can sufficientlyfill the mold completely to the tip ends of the mold, and the resultantmolded article can feel softer and more comfortable in touch because ofthe composition of the skin. When the content of the end oxyethyleneunit is in the range of 10% to 25% by weight, the flowability of theliquid mixture of components (I) and (II) is further improved, and thecuring time becomes suitably longer.

In accordance with the present invention, the polyether polyol of (1)the polyol component may be a mixture of two or more different polyetherpolyols. In this particular case, it is preferable to use thesepolyether polyols in relative amounts such that the averages of thefunctionality, the hydroxyl value and the end oxyethylene unit contentof the mixture are in the range of about 2.0 to about 3.0, the range ofabout 16.8 to about 56 mg KOH/g, and the range of about 10% to about 25%by weight, respectively, and more preferably that the averages offunctionality, the hydroxyl value and the end oxyethylene unit contentof the mixture are in the range of about 2.0 to about 2.5, of about 28to about 50 mg KOH/g, and the range of about 15% to about 20% by weight,respectively.

The chain extender (2) comprises1-methyl-3,5-diethyl-2,4-diaminobenzene,1-methyl-3,5-diethyl-2,6-diaminobenzene and mixtures thereof.

The chain extender (2) is blended in an amount of about 2.0 to about 7.0parts by weight, per 100 parts by weight of (I) the polyol mixture. Whenthe amount of the chain extender (2) is less than 2.0 parts by weight,the amount of the polyisocyanate to necessary react with (I) the polyolmixture becomes smaller, and undesirably, failure in mixing tends tooccur. When this amount exceeds 7 parts by weight, the viscosity of theliquid mixture quickly becomes too high due to the reaction, which leadsto poor flowability of the liquid mixture of components (I) and (II)such that they are unsuitable for practical use.

By using the chain extender (2) in an amount of 2.0 to 7.0 parts byweight, the flowability of the liquid mixture of components (I) and (II)is not impaired even when a thin layer of the non-foaming polyurethaneresin having a thickness of 0.5 to 3.0 mm is formed. In addition, themixing performance is still sufficient, as is the reactivity, and thecuring time for molding can be controlled to 30 to 100 seconds, evenwhen the mixing ratio of (I) the polyol mixture to (II) thepolyisocyanate compound is decreased to 100 parts by weight (I) to 14parts by weight (II).

The chain extender described above may be used in combination with anyother chain extenders comprising aromatic polyamines, provided thephysical properties of the resultant skin of the present invention arenot impaired.

It is possible to mold a polyurethane resin layer with a thickness asthin as 0.5 mm up to 3.0 mm by a RIM process, using a polyurethane rawmaterial comprising a glycol type chain extender such as monoethyleneglycol, propylene glycol, butane diol, diethylene glycol or the like. Inthis case, however, the cure time needed is about 120 to about 180seconds. This is because the liquid mixture shows too high a flowresistance to form such a thin layer, and it is necessary to have suchreactivity as to sufficiently decrease the thickening rate during thereaction, in order to completely fill the polyurethane raw material upto the tip ends of the mold. In the meantime, to obtain a polyurethaneresin layer feeling soft in touch, the surface hardness thereof isgenerally lowered by decreasing the amount of a glycol type chainextender. However, a polyurethane raw material comprising a glycol typechain extender such as, for example, monoethylene glycol, becomes hardto mix, when the mixing ratio of (I) the polyol mixture to (II) thepolyisocyanate compound is less than 100 parts (I) to 25 parts (II) (byweight), so the amount of the polyisocyanate is decreased. Consequently,the resultant molded article tends to crack or blister due to thefailure in mixing, and the reactivity of the polyurethane raw materialbecomes extremely low, so that a cure time of about 180 to about 300seconds is necessary for a polyurethane raw material containing aglycol.

Suitable for use as (3) the catalyst are those conventionalurethane-forming catalysts. The urethane-forming catalysts arecategorized as amine catalysts, metal catalysts and the like. Examplesof suitable amine catalysts include tertiary amines such astriethylenediamine, pentamethyldiethylenetriamine,1,8-diazabicyclo-5,4,0-undecene-7, dimethylaminoethanol,tetramethylethylene-diamine, dimethylbenzylamine,tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)-ether,N,N′-dimethylaminopropylamine, N,N′-dimethylaminopropanol,N,N′-dimethylethanolamine, and 1-isobutyl-2-methylimidazole; as well astertiary amines such as N-methyl-N′-hydroxyethyl-piperazine,N,N′-dimethylaminoethoxyethanol, andN,N′-trimethylamino-ethylethanolamine. Examples of suitable metalcatalysts include dimethyltin dilaurate, dibutyltin dilaurate, potassiumacetate, potassium octylate, potassium lactate, and stannous dioctoate.In accordance with the invention, component (3) the catalysts may beused alone or in combination with each other. Thus, each of the aminecatalysts and each the metal catalysts may be used alone, andpreferably, an the amine catalyst is used in combination with a metalcatalyst.

The amount of the catalyst is adjusted such that the gel time of theliquid mixture of components (I) and (II) are within a range of 5.0 to15.0 seconds. When the gel time is within the range of 5.0 to 15.0seconds, the polyurethane raw material can be molded in a cure time asshort as 30 to 100 seconds. The amount of component (3), the catalyst,is preferably from about 0.01 to about 2.00 parts by weight, morepreferably about 0.10 to about 1.60 parts by weight, based on 100 partsby weight of (I) the polyol mixture. When the amine catalyst is used incombination with the metal catalyst, the amount of the amine catalyst isabout 0.1 to about 1.5 parts by weight, preferably about 0.2 to about1.3 parts by weight, per 100 parts by weight of (I) the polyol mixture;and the amount of the metal catalyst is about 0.01 to about 0.10 partsby weight, and preferably about 0.03 to about 0.07 parts by weight, per100 parts by weight of (1) the polyol mixture.

The gel time is determined as follows: the liquid mixture (200 g) of (I)the polyol mixture and (II) the polyisocyanate compound is charged intoa 500 ml polyester cup, under conditions that a high-pressure moldingmachine uses for molding, including that the temperature of the liquidmixture of components (I) and (II) is maintained at 30° C., and that thedischarge rate is controlled at 200 g/sec. A tooth-pick is pushed in orout of the surface of the liquid mixture of components (I) and (II)which starts to react, so as to determine the gel time.

The term “gel time” as used herein referred to the period of time takenfor the liquid mixture of components (I) and (I), which starts to react,to allow thread-like matters (i.e. gel) to be drawn therefrom, from thestart of charging the liquid mixture.

If needed, component (4) one or more auxiliary agents may be added.Examples of (4) auxiliary agents include a foam stabilizer such as asilicon type foam stabilizer, a surfactant, a filler, a weathering agentsuch as an antioxidant and/or a UV absorber, and a stabilizer such as,for example, 2,6-di-t-butyl-4-methylphenol,tetrakis[methylene-3-(3′,5′-di-t-butyl-4-hydroxyphenyl)propionate]methane,etc. The amount of the auxiliary agent to be added is typically notlarger than 20% by weight such as, for example, 0.1 to 10% by weight,based on the total weight of the composition for polyurethane.

The polyol mixture, component (I), is prepared as a non-foaming polyolmixture, without adding water or any of foaming agents such as, forexample, CFC and HCFC. The inclusion of water, such as the water contentoriginally contained in the raw materials of the polyol mixture (I) andthe water content included in the polyol mixture (I) while beinghandled, is unavoidable. However, the amount of water in (I) the polyolmixture is preferably 0.15% or less.

As (II) the polyisocyanate compound of the present invention, suitablepolyisocyanate compounds include those having at least two isocyanategroups in the molecule, which are known to be suitable for use inconventional polyurethane resin compositions. Examples of suitablepolyisocyanates for (II) include aromatic isocyanates such asdiphenylmethanediisocyanate, trilenediisocyanate,polyphenylenepolymethylene polyisocyanate, xylilenediisocyanate,tetramethylxylilene diisocyanate, and 1,5-naphthalenediisocyanate;urethane-modified polyisocyanates, carbodiimide-modified polyisocyanatesand isocyanurate-modified polyisocyanates obtained from theseisocyanates.

Among these polyisocyanate compounds, the aromatic polyisocyanates andthe modified products thereof are preferred because of theirreactivities and the costs thereof. When the polyurethane resin isrequired to have light resistance, it is preferable to apply a coatinghaving light resistance to the surface of the resin.

The mixing ratio of (I) the polyol mixture to (II) the polyisocyanatecompound is preferably from 90 to 125, in terms of the isocyanate index[(i.e. the ratio of the equivalents of the isocyanate groups in (II) thepolyisocyanate compound to the equivalents of the active hydrogen in (I)the polyol mixture,)×100].

The density of the non-foaming polyurethane resin of the presentinvention is preferably about 1.00 g/cm³ to about 1.10 g/cm³, morepreferably about 1.05 g/cm³ to about 1.10 g/cm³. When this density isabout 1.00 g/cm³ to about 1.10 g/cm³, no foam is visually observed, sothat such a non-foaming polyurethane resin can be preferably used as askin for a design face of an interior article. When the water content ofthe polyol mixture (I) is not larger than about 0.15%, the density ofthe non-foaming polyurethane resin becomes substantially the same valueas a density attributed to the mixing ratio of the liquid mixture ofcomponents (I) and (II). Thus, a non-foaming polyurethane resin with adensity of 1.0 g/cm³ to 1.10 g/cm³ can be obtained.

The RIM process can be carried out with any of the conventional RIMmachines such as, for example, the “A system high-pressure reactionmachine” which is manufactured by CANON INC.

The liquid temperatures of (I) the polyol mixture and (II) thepolyisocyanate compound during the RIM process are preferably within arange of 30 to 40° C. Within this range of temperatures, the reactivityand viscosity of the liquid mixture of components (I) and (II) aresuitable, and the flowability thereof is good.

The temperature of the mold is preferably 50 to 80° C., and morepreferably 50 to 60° C. When the temperature of the mold is 50 to 80°C., the liquid mixture of components (I) and (II) can be smoothlyreacted to form polyurethane in a cure time of 30 to 100 seconds.

In case where a raw material satisfying the following condition issubjected to the RIM process with the temperature of the mold controlledat a temperature of 50 to 80° C., the flowability of the liquid mixtureof components (I) and (II) is not impaired, and a cure time as short as30 to 100 seconds is sufficient for the molding, even when a thin layerof a non-forming polyurethane resin with a thickness of 0.5 to 3.0 mm isformed by molding. In this regard, the above described conditionrequires that the raw material contains1-methyl-3,5-diethyl-2,4-diaminobenzene,1-methyl-3,5-diethyl-2,6-diaminobenzene or mixtures thereof as the chainextender (2), in an amount 2.0 to 7.0 parts by weight per 100 parts byweight of the polyol mixture (I), and (3) the catalyst in such an amountthat the gel time of the liquid mixture of components (I) and (II) canbe from 5.0 to 15.0 seconds. When, for example, a raw material using (3)the catalyst in such an amount that the gel time of the liquid mixtureof components (I) and (II) can be 8 seconds is subjected to a RIMprocess, with the temperature of a mold controlled at 55° C., the rawmaterial can be molded in a cure time of as little as 60 seconds.

The surface hardness of the non-foaming polyurethane resin thus obtainedis preferably 30 to 70 as measured with an Asker A hardness meter, andmore preferably 30 to 60. At these Asker A hardness levels, the resinlayer feels soft and comfortable in touch.

As a comparative trial, a non-foaming polyurethane resin layer with athickness as so thin as 0.5 mm to 3.0 mm was formed by a RIM process,with the temperature of the mold controlled at 50 to 80° C., from apolyurethane raw material which contained a glycol type chain extendersuch as, for example, monoethylene glycol, and the amount of thecatalyst (3) present was such that the gel time of the liquid mixture ofcomponents (I) and (II) could be 5.0 to 15.0 seconds. As a result, acure time of about 120 to about 180 seconds was needed for the rawmaterial to be molded.

An interior article of the present invention which is a skin-integratedlaminate comprising a non-foaming polyurethane resin and a corematerial, and particularly a skin-integrated molded article which issuitable for use in a vehicle interior article, can be manufactured by amethod comprising the following steps:

-   (1) installing a core material into a core part of a mold,-   (2) applying a mold release agent on the surface of a cavity part of    the mold,-   (3) optionally, forming or applying a coating film on the surface of    the cavity part of the mold, by a suitable coating process,-   (4) closing the core part and the cavity part of the mold,-   (5) reaction injection molding a liquid mixture of (I) the polyol    mixture and (II) the polyisocyanate compound into the unfilled    portion of the closed mold, and-   (6) removing the molded article integrated with a skin from the    mold.

In this manufacturing method, the core part of the mold refers the sidepart of the mold on which the core material is installed, and the cavitypart of the mold refers to the side part of the mold on which is adesign surface or on which a design surface is capable of being formed.

The core material is previously formed in the shape of theskin-integrated molded article for the vehicle interior article.Examples of suitable core materials include polypropylene resins,polycarbonate/ABS resins, ABS resins, and polyurethane resins. Inparticular, the polypropylene resins are widely used.

The mold release agent may be any of wax type and water type which issuitable for use in the conventional RIM process.

The coating film to be applied on the surface of the cavity part shouldhave photostability and wear resistance properties.

In the above described manufacturing method, the non-foamingpolyurethane resin which forms the skin is not prepared by spraying.Accordingly, there is no over-spray of the liquid mixture of components(I) and (II) which occurs, and no adverse influence on the workenvironment and/or nature occurs as a result of this process. Inaddition, the skin material can be manufactured at a higher productionefficiency with less waste of raw materials during the manufacturing,which leads to a further decrease in the manufacturing cost,particularly when compared with other skin materials such as PVC, TPOand TPU.

Furthermore, there is no problem with air or moisture in the air beingincorporated into the raw materials since spraying is not being used.Thus, the foaming of the non-foaming polyurethane resin or the formationof bubbles with larger sizes in the non-foaming polyurethane resin isunusual and does not typically occur in the present invention.Consequently, the skin which forms the design face of the interiorarticle is not so expanded due to an increase in temperature in thepresent invention. Over-expansion of the skin can be visually recognizedas a fatal defect in view of the external appearance of the design face.

According to the present manufacturing method, the interior articlewhich is the skin-integrated laminate comprising the non-foamingpolyurethane resin and the core material can be manufactured with onemold by one shot of the non-foaming polyurethane resin, and in a shortermolding time which corresponds to the cure time of the non-foamingpolyurethane resin, i.e., 30 to 100 seconds. Thus, the highly efficientmanufacture of the skin-integrated laminate and the reduction of themanufacturing cost are now possible.

In addition, there can be produced a skin-integrated molded articlesuitable for a vehicle interior article in accordance with the presentinvention, which comprises, as a design layer, the non-foamingpolyurethane resin layer which has a thickness as thin as 0.5 mm to 3.0mm, but feels soft and comfortable to touch.

In addition to the above manufacturing method, an interior article, andspecifically a skin-integrated molded article suitable for a vehicleinterior article, which is a skin-integrated laminate comprising anon-foaming polyurethane resin, a semi-rigid polyurethane foam and acore material, can be manufactured in accordance with the presentinvention. This method comprises the steps of:

-   (1) applying a mold release agent onto the interior surfaces of a    core part and a cavity part of a mold which is suitable for shaping    or forming a skin as the design face of a molded article,-   (2) optionally forming or applying a coating film on the surface of    the cavity part of the mold, by a suitable coating process,-   (3) closing the core part and the cavity part of the mold,-   (4) reaction injection molding a liquid mixture comprising (I) the    polyol mixture as described above and (II) the polyisocyanate    compound as described above into the closed mold,-   (5) removing molded product of the non-foaming polyurethane resin    which is suitable as the skin for the design face,-   (6) placing or setting the molded product of the non-foaming    polyurethane resin produced in step (5), in the cavity part of the    mold for shaping a foam,-   (7) installing a core material on the core part of the foam-shaping    mold from step (6),-   (8) injecting or pouring a semi-rigid polyurethane foam onto the    non-foaming polyurethane resin molded product placed or set in the    cavity part of the mold employed in step (6), with the mold being    either opened or closed, and-   (9) removing the resultant molded article integrated with the skin.

In the above process, step (8) of injecting or pouring the semi-rigidpolyurethane foam when the mold is opened is carried out by injectingthe semi-rigid polyurethane foam onto the molded product of thenon-foaming polyurethane resin previously placed or set in the cavitypart of the foam-shaping mold, and then closing the core part and thecavity part of the foam-shaping mold. On the other hand, step (8) ofinjecting the semi-rigid polyurethane foam when the mold is closed iscarried out by subjecting the semi-rigid polyurethane foam mixture toreaction injection molding such that it enters into the space betweenthe molded part of non-foaming polyurethane resin and the core material,while the core part and the cavity part are closed. Either of thesemethods may be selected, as desired or required.

In the above described manufacturing method, two molds are needed. Inparticular, one mold (i.e. a first mold) is needed for shaping andforming the non-foaming polyurethane resin which is suitable for use asthe skin, and the other mold (i.e. the second mold) is needed forinjecting or pouring the semi-rigid polyurethane foam. The first mold isused in steps (1) through (5) of the above process, and the second moldis used in steps (6) through (9) of the above described process.

The semi-rigid polyurethane foam of this method can be prepared byblending the conventional raw materials which are known to be suitablefor the production of crush pads (e.g., a polyisocyanate component and apolyol component), and curing the mixture.

The density and hardness of the semi-rigid polyurethane foam may beoptionally adjusted according to a desired end use. In accordance withthe present invention, it is possible to form semi-rigid polyurethanefoams having a density of 0.12 to 0.23 kg/cm³ and a surface hardness of35 to 50 measured with an Asker C hardness meter. For example, asemi-rigid polyurethane foam having a density of 0.185 g/cm³ and asurface hardness of 40 measured with an Asker C hardness meter can beused.

The core material may be the same one as that used in the conventionallaminate comprising the non-foaming polyurethane resin and the corematerial. If necessary, to improve the adhesion between the corematerial and the semi-rigid polyurethane foam, the surface of the corematerial may be subjected to a flame treatment or plasma treatment. Itmay also be treated to impart an anchoring effect or may be coated witha primer for improving the adhesiveness.

In, or preferably before step (6) of the above described process, it ispreferred to remove any of the wax type or water type mold release agentwhich is typically used in a RIM process, from the surface of thenon-foaming polyurethane resin which will be in contact with thesemi-rigid polyurethane foam. This is to ensure the adhesion between thenon-foaming polyurethane resin molded product obtained in the step (5)and the semi-rigid polyurethane foam that is formed in the second mold.

Also, the coating film which is formed or applied onto the surface ofthe cavity part of the mold may be the same one as the previouslydescribed coating film that is characterized by light stability and wearresistance properties, of the conventional laminate comprising thenon-foaming polyurethane resin and the core material.

Also, in the present manufacturing method, the non-foaming polyurethaneresin which is suitable for use as the skin is not formed by spraying.Therefore, no over-spray of the liquid mixture comprising components (I)and (II) occurs, and thus, there is no adverse influence on the workenvironment and/or nature. Furthermore, the skin material can bemanufactured in higher production efficiency with less waste of rawmaterials during the manufacturing. This also leads to a decrease in themanufacturing cost, particularly in comparison with other skin materialssuch as PVC, TPO and TPU.

In addition, there is no incorporation of the air or the moisture in theair into the raw material which is being sprayed in accordance with thepresent invention. Thus, the foaming of the non-foaming polyurethaneresin and/or the formation of bubbles with larger sizes rarely results.Consequently, the skin which is suitable as a design face for aninterior article is not over expanded due to an increase in temperature,which can be visually recognized as a fatal defect in view of theexternal appearance of the design face.

Furthermore, there is typically no formation of bubbles with largersizes, and accordingly, the non-foaming polyurethane resin moldedproduct is not impregnated with the semi-rigid polyurethane foam. Thus,the non-foaming polyurethane resin molded product which is suitable foruse as the skin feels smooth to touch, without any inharmonious feelingdue the impregnation.

In accordance with the present invention, the manufacture of askin-integrated molded article for a vehicle interior article, whichcomprises the core material, the semi-rigid polyurethane foam, and thenon-foaming polyurethane resin as the skin for a design face, in whichthe skin which has a thickness of 0.5 mm to 3.0 mm, and feels soft andcomfortable to touch.

The following Examples further illustrate the present invention indetail. The present invention is not restricted by these Examples. Partsand % in these examples are parts by weight and weight %, respectively.

EXAMPLES

Each of the performance evaluation method and the evaluation standardfor non-foaming polyurethane resin are as described below:

(1) Sample Preparation

-   -   The samples for evaluation were prepared by using a mold having        the size of 900 mm×300 mm×1 (thickness) mm by a RIM molding        process using, for example, the “A System high pressure reaction        machine” manufactured by Canon Inc. (Throughout the        specification, the letter “t” is used to designate thickness.)        At the time of molding, the discharge rate of mixture liquid (I)        and (II) was 200 g/second and the mixing pressure was 15 MPa.        The surface temperature of the mold was adjusted at 55° C.        (2) Evaluation Standard for the Curing Time    -   The surface appearance of molded article which was removed from        the mold was observed by determining the state of “without        blister” and “without roughness” by the visual observation. The        time from pouring the mixture liquid (I) and (II) into the mold        until opening of the mold is taken as the cure time.        (3) The Evaluation Standard on Mixing Performance by Stirring    -   Good: There was no crack and blister of the molded article which        was caused by the lack of mixing and stirring.    -   Bad: There was crack and/or blister of the molded article which        was caused by the lack of mixing and stirring.        (4) The Evaluation Method and Evaluation Standard on Flowability    -   Good: The mixture liquid (I) and (II) flowed completely into the        ends of mold and there were no parts of molded article that were        unfilled.    -   Bad: The mixture liquid (I) and (II) did not flow completely        into the ends of mold, and there were parts of the molded        article that were unfilled.

-   (5) The Measurement of the Tensile Strength (MPa), the Elongation    (%) at Break and the Surface Hardness    -   The measurement of the tensile strength (MPa) and the elongation        (%) at break were cared out at room temperature using an Auto        Graph AG-1(1KN) manufactured by Shimadzu Corporation.    -   The surface hardness was measured at 25° C. by an Asker A        hardness meter.        The Evaluation of a Skin-Integrated Molded Article Comprising        Laminate of a Non-foaming Polyurethane Resin and a Core Material

-   (1) The mold with the size of 300 mm×900 mm×4.0 (t) mm was used for    preparation of the molded article. The core material made of    polypropylene with about 3.0 mm thickness was fixed in the core mold    by the double-stick tape in order to adjust the thickness of the    non-foaming polyurethane resin to 1 mm. Then the skin-integrated    molded article was made by the RIM molding after closing the mold.    At the time of molding, the discharge rate of mixture liquid (I)    and (II) was 200 g/second and the mixing pressure was 15 MPa. The    surface temperature of mold was adjusted at 55° C.

-   (2) The curing time, the evaluation of mixing performance by    stirring, evaluation of flowability and the measurement of the    surface hardness were carried out in the same manner as in the    performance evaluation method and the evaluation standard of    non-foaming polyurethane resin.

-   (3) The bonding property between non-foaming polyurethane resin and    core material made of polypropylene just after curing was determined    by checking whether the delamination occurred between the skin made    of non-foaming polyurethane resin and core material of polypropylene    by visual observation.

The evaluation standard on the bonding property is as follows:

Good: Delamination was not caused.

Bad: Delamination was caused.

The Evaluation of a Skin-Integrated Molded Article Comprising theLaminate of a Non-Foaming Polyurethane Resin, a Semi-Rigid PolyurethaneFoam and a Core Material

-   (1) A non-foaming polyurethane resin with about 1.0 mm thickness    prepared by the same preparation method as set forth above, was set    onto the cavity part of an article mold with the size of the mold    being 300 mm×900 mm×11.0 (t) mm, and then the core material made of    polypropylene with about 3 mm thickness was fixed on the core mold    by the double-stick tape. After the mold was closed, the raw    material for a semi-rigid polyurethane foam with the density of    molded article of 0.185 g/cm³ was poured and foamed between the core    material and the non-foaming polyurethane resin by the RIM molding.    This formed an integral molding with skin.-   (2) The semi-rigid polyurethane foam was poured using the “A System    high pressure reaction machine” manufactured by Canon Inc.

The pouring quantity was 180 to 350 g/second.

The mixing pressure was 15 MPa. The pouring time was 1.2 to 2.5 seconds.

The temperature of mold was adjusted at 40° C.

-   (3) The evaluation of the integral molding with skin was done to    determine whether the blister affected the quality of appearance on    the non-foaming polyurethane which formed the skin of the integral    molding by visual observation. The surface hardness was measured by    an Asker A hardness meter and its surface hardness was assessed as    to whether tactile impression was good or not.    The Judgment Standard for “Blister”

Good means that “blister” was not observed and the bonding property wasgood as there was no delamination with a semi-rigid polyurethane foam.

Bad means that “blister” was observed and the bonding property was badas there was delamination with a semi-rigid polyurethane foam.

The types of starting materials, including functionality and hydroxylvalue (mg KOH/g) of a polyether polyol used as the polyol in polyolmixture (I), chain extenders, catalysts, and various polyisocyanatecompounds used as component (II) are described in Table 1.

The actual formulations of different non-foaming polyurethane resinmoldings are shown in Table 2, and the results of the evaluation ofthese moldings are shown in Table 3.

The results of evaluation on the skin-integrated molded articlecomprising the laminate of a non-foaming polyurethane resin and a corematerial were shown in Table 4.

Example 1

By the using a polyol mixture (I) and a polyisocyanate compound (II),the details of which are shown in Table 1, the non-foaming polyurethaneresin sample was prepared for evaluation using the formulation shown inTable 2 and a mold with the size of 900×300×1 (t) mm by the RIM processin the “A System high pressure reaction machine” manufactured by theCanon Inc. The surface temperature of the mold was adjusted to 55° C.

At the time of molding, the temperature of the polyol mixture (I) andthe polyisocyanate compound (II) were adjusted to 30° C., the dischargerate of the liquid mixture comprising components (I) and (II) was 200g/second and the mixing pressure was 15 MPa.

As shown in Table 3, the gel time was 8 seconds, the cure time was 60seconds, the mixing performance and flowability were good and theresultant non-foaming polyurethane resin had the qualities of goodappearance and good tactile impression, with the Asker A hardness ofsurface of 60.

Example 2

By using a polyol mixture (I) and a polyisocyanate compound (II), thedetails of which are shown in Table 1, the non-foaming polyurethaneresin sample were prepared for evaluation using the formulation shown inTable 2, and under the same molding conditions as described in Example1.

As shown in Table 3, the gel time was 14 seconds, the cure time was 70seconds, the mixing performance and flowability were good and theresultant non-foaming polyurethane resin had the qualities of goodappearance and good tactile impression, with the Asker A hardness ofsurface of 49.

Example 3

By the using a polyol mixture (I) and a polyisocyanate compound (II),the details of which are shown in Table 1, the non-foaming polyurethaneresin sample was were prepared for evaluation using the formulationshown in Table 2, and under the same molding conditions as describedabove in Example 1.

As shown in Table 3, the gel time was 11 seconds, the cure time was 60seconds, the mixing performance and flowability were good and theresultant non-foaming polyurethane resin had the qualities of goodappearance and good tactile impression, with the Asker A hardness ofsurface of 53.

Example 4

By the using a polyol mixture (I) and a polyisocyanate compound (II),the details of which are shown in Table 1, the non-foaming polyurethaneresin sample was prepared for evaluation using the formulation shown inTable 2, and under the same molding conditions as described above inExample 1.

As shown in Table 3, the gel time was 9 seconds, the cure time was 60seconds, and the mixing performance and flowability were good and theresultant non-foaming polyurethane resin had the qualities of goodappearance and good tactile impression, with the Asker A hardness ofsurface of 60.

Comparative Example 1

By the using a polyol mixture (I) and a polyisocyanate compound (II),the details of which are shown in Table 1, the non-foaming polyurethaneresin sample was prepared for evaluation using the formulation shown inTable 2 and under the same molding conditions as described above inExample 1.

As shown in Table 3, the gel time was 6 seconds, the cure time was 150seconds, the flowability was good, but mixing performance was not good.

The appearance of the resultant molded article was bad due to theblister and crack which were observed in the molded article aftercuring.

Comparative Example 2

By the using a polyol mixture (I) and a polyisocyanate compound (I), thedetails of which are shown in Table 1, the non-foaming polyurethaneresin sample was prepared for evaluation using the formulation shown inTable 2 in which the quantity of chain extender comprising ethyleneglycol was increased to 3 parts by weight from that in ComparativeExample 1 as shown in Table 2, and under the same molding conditions asdescribed above in Example 1.

As shown in Table 3, the gel time was 5 seconds, but the cure time was120 seconds.

Comparative Example 3

By the using a polyol mixture (I) and a polyisocyanate compound (II),the details of which are shown in Table 1, the non-foaming polyurethaneresin sample was prepared for evaluation using the formulation shown inTable 2. Specifically, this formulation varied from the invention inthat the quantity of diethyl-diaminotoluene, i.e. the chain extender,was increased to 10 parts by weight from the amount used Example 4 asshown in Table 2. The same molding conditions as described above inExample 1 were used.

As shown in Table 3, the cure time was 60 seconds, but the gel time wasonly 3 seconds. This gel time was too fast. In fact, the gel time was sofast that the liquid mixture didn't flow completely to the end of moldand this resulted in a portion of the mold being unfilled. Also, theflowability was not good. The resultant non-foaming polyurethane resindid not have good tactile impression because of the Asker A hardness ofsurface of 77 was too hard.

Example 5

The evaluation of a skin-integrated molded article comprising thelaminate of a non-foaming polyurethane resin and a core material

The core material which was made of polypropylene and having a thicknessof about 3.0 mm was placed in the core part of article mold usingdouble-stick tape. The mold size was 300 mm×900 mm×4.0 (t) mm, and thesurface temperature of the mold was adjusted to 55° C. Then, the moldrelease agent (Wax system RIM mold release agent B308-10, commerciallyavailable from Cyukyo Yushi Co., Ltd.) was coated on the surface ofcavity portion of the article mold and the core part and the cavity partof article mold was closed.

Then, reaction injection molding was carried out by the discharge of aliquid mixture comprising components (I) and (II) as shown in Table 1for Example 3. The temperature of the mold was adjusted to 30° C., thedischarge rate was 200 g/second, and the mixing pressure was 15 MPa, asdescribed above in Example 1.

After the integral molding with a non-foaming polyurethane resin and acore material made of polypropylene was completed and the resultantintegral molding was removed from the mold, the evaluation of theskin-integrated molded article comprising the laminate of thenon-foaming resin and a molded core material was carried out.

The thickness of non-foaming polyurethane resin as the skin of theresultant laminate was 1.0 mm and the cure time of the skin-integratedmolded article was 60 seconds from the time of pouring the non-foamingpolyurethane resin. There was no delamination observed between thenon-foaming polyurethane resin and core material made of polypropylene.

The resultant skin-integrated molded article had an excellent qualityappearance of the skin, a density of 1.05 g/cm³, and good tactileimpression which was soft in terms of feel, with the Asker A hardness ofsurface of 53.

Example 6

The evaluation of a skin-integrated molded article comprising thelaminate of a non-foaming polyurethane resin, a semi-rigid polyurethanefoam and a core material:

The evaluation of a skin-integrated molded article comprising thelaminate of a previously painted non-foaming polyurethane resin whichwas prepared using the formulation as described in Example 2, asemi-rigid polyurethane foam for a crush pad and a core material (ofpolypropylene) was carried out.

First, the non-foaming polyurethane resin used for a design surface skinwas molded. Then, the mold release agent (Wax system RIM mold releaseagent B308-10, commercially available from Cyukyo Yushi Co., Ltd.) wascoated on the core part and cavity part of article mold for the skin.The mold size was 300 mm×900 mm×1.0 (t) mm, and the surface temperaturewas adjusted to 55° C. A paint film was made on the whole surface of thecavity part. Then, the core part of article mold for the skin and thecavity part of article mold was closed. After that, the reactioninjection molding was carried out by the discharge of the liquid mixturecomprising components (I) and (II), which consisted of a polyol mixture(I) and a polyisocyanate compound (II) as described in Example 2, withthe mold temperature being adjusted to 30° C. The resultant non-foamingpolyurethane resin molded article having a thickness of 1.0 (t) mm wasremoved from the mold. Following this, the resultant non-foamingpolyurethane resin molded article was placed on the cavity portion of anarticle mold for foaming, in which the mold size was 300 mm×900 mm×11.0(t) mm, and wherein the temperature of the whole mold was adjusted to40° C. The core material made of polypropylene which was about 3.0 mmthick, was fixed on the core part of foaming mold using double-sticktape, and the mold was closed.

Onto the molded article of the non-foaming polyurethane resin which wasplaced on the cavity portion of the foaming mold, was poured a mixtureof raw materials for forming a semi-rigid polyurethane foam to yield amolded article density of 0.185 g/cm³, such that the semi-rigidpolyurethane foam was formed by reaction injection molding the mixtureof raw materials between the core material and the non-foamingpolyurethane resin. The temperature of the mold was adjusted to atemperature of 25° C. The RIM process used the “A System high pressurereaction machine” manufactured by the Canon Inc., at a discharge rate of300 g/second, a mixing pressure of 15 MPa and a pouring time of 2.0seconds, to yield the integral molding with skin. Upon removing theintegral molding with skin from the mold, a skin-integrated moldedarticle comprising the laminate of a non-foaming polyurethane resin, asemi-rigid polyurethane foam and a core material was obtained.

The resultant skin-integrated molded article had good tactile Impressionand was very soft in terms of feel, with the Asker A hardness of surfaceof 40. Additionally, no blister formation was observed on thenon-foaming polyurethane resin which formed the skin. The resultantskin-integrated molded article had an excellent quality appearance, withexcellent bonding properties including no delamination between the skinand the semi-rigid polyurethane foam.

TABLE 1 Description of Components for Polyol mixture (I) andPolyisocyanate compound (II) Polyol mixture (I) Polyether polyol (1)Starter: propylene glycol Average functionality: about 2.0, Hydroxylvalue of polyether polyol: 45 mg KOH/g Chain extender (2) Chain extender(2 - 1) diethyldiaminotoluene Chain extender (2 - 2) ethylene glycolCatalyst (3) Catalyst (3 - 1) 33% solution of triethylenediamine inpropylene glycol Catalyst (3 - 2) dibutyltin dilaurate Polyisocyanatecompound (II) Polyisocyanate compound (II - 1): Carbodiimide-uretoiminemodified diphenylmethane diisocyanate NCO %: 29.0%, viscosity: 40 mPa ·s/25° C. Polyisocyanate compound (II - 2): Urethane modified isocyanateprepolymer based on diphenylmethane diisocyanate (NCO %: 17.0%,viscosity: 1000 mPa · s/ 25° C.) and polyol (average functionality: 3,average molecular weight: 6,000) Polyisocyanate compound (II - 3):Polymethylene polyphenyl polyisocyanate NCO %: 31.5%, viscosity: 180 mPa· s/25° C.

TABLE 2 Formulation for non-foaming polyurethane resin moldings ExamplesComparative Examples 1 2 3 4 1 2 3 Polyol mixture (I) Polyether polyol93.95 93.55 96.75 93.95 96.85 95.35 88.95 (1) (pbw) Chain extender 5 5 25 10 (2-1) (pbw) Chain extender 1.5 3 (2-2) (pbw) Catalyst (3-1) (pbw)0.6 1.0 0.8 0.6 1.2 1.2 0.6 Catalyst (3-2) (pbw) 0.05 0.05 0.05 0.050.05 0.05 0.05 Weathering agent 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Total 100100 100 100 100 100 100 Hydroxyl value 77.1 79.2 60.6 77.1 77.4 103.8106.4 (mg KOH/g) Polyisocyanate compound (II) Polyisocyanate x compound(II-1) Polyisocyanate x compound (II-2) Polyisocyanate x x x x xcompound (II-3) NCO Index 105 105 105 105 105 105 105 Mixing Ratio (pbw)100/20.9 100/36.6 100/15.1 100/19.3 100/19.3 100/25.9 100/26.6 Polyolmixture (I)/ Polyisocyanate compound (II)

TABLE 3 Evaluation of non-foaming polyurethane resin molding ExampleComparative Example 1 2 3 4 1 2 3 Temperature of raw 30 30 30 30 30 3030 material (° C.) Pouring quantity 200 200 200 200 200 200 200 (g/sec.)Reaction property 8 14 11 9 6 5 3 gel time (sec.) Thickness (mm) 1.0 1.01.0 1.0 1.0 1.0 1.0 Cure time (sec.) 60 70 60 60 150 120 60 Mixingperformance Good Good Good Good Bad Good Good Flowability Good Good GoodGood Good Good Bad Physical property Density (g/cm³) 1.05 1.02 1.05 1.051.05 1.05 n.d. Asker A hardness of 60 49 53 60 60 75 77 surface Tensile4.6 3.4 4.0 3.7 n.d. 4.1 n.d. strength(MPa) Elongation at break 440 415420 165 n.d. 80 n.d. (%) Tearing strength 240 195 200 142 n.d. 135 n.d.(N/cm) n.d. not determined

TABLE 4 Evaluation on the skin-integrated molded article comprising alaminate of non-foaming polyurethane resin and core material Example 5Temperature of raw material 30 (° C.) Pouring quantity (g/sec.) 200Thickness (mm) 1 Cure time (sec.) 60 Mixing performance Good Flowability— Good Bonding property Good Physical property Density (g/cm³) 1.05Asker A hardness of surface 53

EFFECT OF THE INVENTION

in accordance with the present invention, a monolithic skin-integratedlaminate suitable for use as an interior article, particularly a vehicleinterior article, can be formed which has a very soft feeling, anexcellent quality appearance and also forms a skin having excellentmoldability. Since, in accordance with the present invention, thereaction time of polyurethane is shortened, the cycle time is shortenedand yield is improved, due to necessity of minimum size of the designsurface. Accordingly, the production cost can be decreased and urethanemist does not result, thus, having no adverse effect on the workenvironment.

Although the invention has been described in detail in the foregoing forthe purpose of illustration, it is to be understood that such detail issolely for that purpose and that variations can be made therein by thoseskilled in the art without departing from the spirit and scope of theinvention except as it may be limited by the claims.

1. A method of producing a skin-integrated laminate comprising a designsurface of a non-foaming polyurethane resin, a semi-rigid polyurethanefoam and a core material, which comprises the steps of: (1) applying amold release agent on a core part and a cavity part of an article moldfor the surface skin which forms the design surface; (2) optionally,applying a paint film on the cavity surface of an article mold; (3)closing the core part and the cavity part of the article mold; (4)reaction injection molding a mixture comprising (I) a polyol mixture,and (II) a polyisocyanate compound, wherein (I) said polyol mixturecomprises: (1) a polyol, (2) from 2.0 to 7.0 parts by weight, based on100 parts by weight of (I) the polyol mixture, of a chain extender, thechain extender being selected from the group consisting of1-methyl-3,5-diethyl-2,4-diaminobenzene,1-methyl-3,5-diethyl-2,6-diaminobenzene and mixtures thereof, (3) acatalysts, and (4) optionally, an auxiliary agent; (5) removing themolded article of a non-foaming polyurethane resin which forms thedesign surface skin; (6) placing the molded article of a non-foamingpolyurethane resin from step (5) into a cavity part of a foaming mold,(7) installing the core material to a core part of the foaming mold, (8)pouring a semi-rigid polyurethane foam mixture onto the non-foamingpolyurethane resin which was placed onto the cavity part of the foamingmold in the step (6), with an opened or closed system, and (9) removingthe resultant integral molded article having a design surface skin.